Digester for manufacture of fertilizer



Sept. 30, 1952 w. D. TAYLOR ET AL 2,511,975

DIGESTER FOR MANUFACTURE FERTILIZER Filed June 8. 1949 4 Sheets-Sheet 1 IN VEN TORS Sept. 30, 1952 Q w. D. TAYLOR ET AL- 5 13 DIGESTER FOR MANUFACTURE OF FERTILIZER Filed June 8. 1949 4 Sheets-Sheet 2 AVID/M7511 Sept. 30, 1952 w. D. TAYLOR ET AL DIGESTER FOR MANUFAACTURE OF FERTILIZER 4 She ts-Shet 3 Filed June 8. 1949 3% 5 0 mnmw w 5 "M W .0 R N W? m M5 UWL. 5 ww .56 g Y B Sept. 30, 1952 w. D. TAYLOR ET AL DIGESTER FOR MANUFACTURE OF FERTILIZER 4 Shgts-Sheet 4 Filed June 8. 1949 IN VEN TORS WILL/AM p. MYLQR Patented Sept. 30, 1952 DIGESTER FOR MANUFACTURE OF FERTILIZER William D. Taylor and Edmund W. Voegtlin, East Orange, and Garl E. Schlosser, Livingston, N. J.

Application June 8, 1949, Serial No. 97,722

Claims. (01. 34--54) This invention relates to apparatus for producing fertilizer, and more particularly to digesters used in the conversion by bacterial reduction of organic materials into fertilizer,

One of the objects of the present invention is to provide a digester which is of simple construction, and which is capable of being operated with low power consumption.

Another object of the present inventionis the provision of a digester which comprises a plurality of decks assembled and arranged for operation in such manner as greatly to simplify the construction of, and facilitate the treatment of the source material in, the digester, and also to effect the treatment of said material in its conversion to fertilizer with optimum results. In connection with this object of the invention, it is an important feature to provide for rotation of certain ones of the decks, while other decks may remain stationary.

Another object of the present invention is to make the several decks of the digester in individual units which are easily transportable and may readily be assembled in final superposed relation at the place of installation of the digester.

Another object of the present invention is to make provisions in the digester for power-rotation of alternate ones of the superposed decks relative to the remaining decks and to arrange plows in the digester so that the alternate driven decks constitute the sole motive force required to mix the material in the several decks and to cause its flow through the digester by the plows therein.

Another object of the present invention is to make provisions for adjusting the pitch of the plows from the outside of the digester, thereby to change the mixing characteristics of the source material in the digester and also the rate at which it travels through the latter.

A further object of, the present invention is to make provisions for controlling the flow of air into the various decks of the digester, and also for controlling the exhaust of waste gases and vapors therefrom.

The above and other objects, features and advantages of the present invention will be more fully understood from the following description considered in connection with the accompanying illustrative drawings.

In the drawings:

Fig. 1 is an elevational view of a digester embodying the present invention;

Fig. 2 is a fragmentary top plan view of the digester;

2 Fig. 3 is an enlarged fragmentary section taken substantially on the line 3-3 of Fig. 2;

Fig. 4 is a section taken on the line Fig. 1;

Fig. 5 is tially on the line 5-5 of Fig. 1; and

Fig. -6 is an enlarged section taken on the line 6--6 of Fig. 5.

Referring to the drawings, the reference numeral l0 designates a digester which may advantageously be used in the conversion by bacterial reduction of organic materials into fertilizer for agricultural purposes. prises a series of superposed decks or compartments I2 which, as hereinafter more fullyde scribed, are in communication with each other through openings in their respective bottom walls.

The material to be converted into fertilizer, heref inafter referred to as source-materialj is introduced into the topmost deck l2 of the digester (Fig. 1), and is caused by plows in the several decks l2 to travel progressively through the latter toward and from the lowermost deck. In the" course of its travel through the digester, the

source-material is thoroughly mixed and also I aerated, all asmore fully described hereinafter. Particularly suitable as source-materials for their successful and economic conversion into highgrade fertilizer are organic waste materials such as garbage, sewage sludge and mill waste, for, instance. The source-material is, in conformity with the usual practice, inoculated withvcertain well-known bacteria which, through bacterial reductionof the material, convert the latter, in the course of its travel through the digester, to useful fertilizer.

The several decks l2 of the digester are characterized in that they are formed as individual units which are particularly well suited for easy transportationand ready assembly at the place of installation of the digester. Each of the decks I2 comprises a bottom wall l4 and a preferably cylindrical side wall l6 which may conveniently be mounted on the bottom wall [4 through intermediation of an angle 18 or other fastening means. As best shown in Fig, 3, each deck [2 is open at the top and communicates with the next higher deck through'an opening or passage 20 in the bottom wall M of the latter. Slotted grates may be provided in these openings 20, if desired.

For their firm support in assembled relation. the decks I2 require at the place of installation of the digester a skeleton frame 2| which comprises, in the present instance, a plurality of angularly spaced uprights 22 that may be anchored afragmentary section taken substan- The instant digester com v38 on the base 24 (Fig, 1).

in, or otherwise mounted on, the ground or door .26. Preferably, the floor 24 is in the form of a concrete base for the digester. The uprights 22 may be in the form of channels to the top ends of which are secured, as by angle brackets 25, for instance, cross braces respectively, which are arranged in the radiatin fashion shown. in Fig. 2, and have suitably secured to their inner ends, as at 3d, a bracket 32 for the support of the top end of an upright, preferably cylindrical. colcum 3% (Fig. 3). The lower end of the column 34 may'convenientiy be supported in a bracket In the present instance, the braces 26 extend outwardly beyond the uprights 22 and may conveniently be mounted with their outer ends on any suitable structure, such as the walls of a building, forinstance, in which the digester is installed.

For a reason described hereinafter, alternate ones of the superposed decks [2 are mounted for rotation relative to the remaining stationary decks. Preferably, the top deck 52' and every other deck i2" alternating therewith are rotary, while the other decks l2 are stationary. Each of the rotary decks H?" is journalled on the central column 3 3 by means of a combined journal and thrust bearing 41 (Fig. 3), and rides at its outer periphery on a plurality of supporting rollers 13.5. which are journalled in suitable bearing brackets 44 on at least some of the uprights 22, respectively, In the present instance the rollers 42 are, as shown in Fig. 4 arranged for each rotating deck 12" on alternate ones of the uprights '22. To reduce friction betweenteach rotating deck l2" and the supporting rollers 42 therefor to a minimum, the bottom wall N3 of each of these decks i2 is provided at its outer periphery'with a circularly arranged angle 45 which rides on the adjacent rollers 32.

Each stationarydeck 52" is centered on the column 52!! through in'terinediation of a hub 5i! (Fig. 3). The bottom wall i i of each stationary deck i2' isfatits outer periphery mounted on at least-some of the uprights 22 through intermediation of suitable angle brackets 56, respeci tively (Figs. 1 and 3).

The superposed decks E2 of the digester preferably further supported .in the center thereof by means of spacers 56 (Fig. 3) which surround the column 34 and are interposed between the bearings iii and hubs 52. :1

of successive rotary and stationary decks l2" and 2 respectively.

Thetopniost deck i2 is closedv at the top by a cover 6% (Figs. 2 and 3) which may convenient- 1y be mounted on the bracket 32 and braces 28 as at Bil and E i, respectively. For further reenforcement of the skeleton frame 2! of the di gester, the cover Ell may additionally be mounted on at least some of the uprights 22 by angle brackets respectively.

For reasons described hereinafter, the-bottom wall is of each. except the lowermost, deck 52, as well as the top cover of the digester, is provided with a depending annular skirt lu which may conveniently cc in the form or an angle that extends with its depending flange into overlapping relation with the side wall 5 5 of the next lowermost deck 12 (Fig. 3). and may there. carry in any suitable manner an annular packing '32 with which eiiectively to seal the interior of the adiacent deck l2 from the outside thereof, while permitting relative rotation between the latter and said skirt is. Hence. since the superposed decks 12 are effectively sealed fromthe outside of the digester as shown in 3, provisions are means of made for the introduction of air into each of the decks [2 for the necessary aeration of the source-material therein. To this end, there is provided in each deck i2 an air-inlet conduit or pipe (Figs. 3 and 5), having perforations 32 for the discharge of air therefrom. The air-inlet conduits 86 in the various decks 12 are in communicationwith branches 84, respectively, of a common air supply conduit on the outside of the digester. Communication between the air inlet conduit 83 in each stationary deck 92" and theadjacent branch 8-! of the supply conduit 85 is provided through a suitable fitting 92 in the side wall 15 of the deck (Fig. 3). Communication between the air inlet conduit 80 in each rotary deck l2" and the adjacent branch 8-3 of the air supply conduit 85 is provided through a suitable'fitting 92" in the depending angle 76 on-the next higher stationary deck 12" (Fig. 3). In the case of the topmost rotary deck 12', the air-inlet conduit til therein communicates with the adjacentbranch 8% of the air-supply conduit 86 through a suitable fitting 92' in the depending angle Ill on the top cover 60 of the digest-er. Preferably, the air-inlet conduit 89 in each deck I 2 is provided with anyconventional type of thermostatic valve 9 whichregulates the intake of air in accordance with temperature conditions inside each deck. I V

For the exhaust from each deck l2 of gasesand vapors created in the, process of converting the source material into fertilizer, each deck i 2 is provided with a perforated exhaust conduit 95 (Fig. 5) which may be arranged, and communicats with an adjacent outside branch 98 of a common exhaust conduit Hill, similarly as the air inlet'conduit 8% in the sai'ne deck. Like the air inlet conduits 8%, the exhaust conduits 98 are preferably provided with conventional thermo-- static valves Hi2, respectively, by means of which to regulate the exhaust of the decks in accordance with temperature conditions therein.

It will he understood that as the temperature increases in the respective decks valves 94 and 582 are more fully opened so as to increase the flow of'air into the deck and similarly to allow an increase of flow of gases and vapors out of the deck. l

The rotary decks l2" are simultaneously driven, at a relatively low speed, from a prime mover, such as an electric motor H0, for instance, which may suitably be mounted on the floor 25 (Figs. 1 and 2) To this end, the bottom wall M of each rotary deck i2 suitably carries t its outer periphery a ring gear 5 it which is in permanent communication with a pinion H4 on an upright shaft I I6, journalled in suitable bearing brackets H8 on one of the uprights 22. The lower end of the shaft 86 may be coupled at 520 to the slow shaft I22 of any suitable reduction gearing 12d of the other shaft I26 of which may conveniently be'coupled at I28 to the shaft of the motor H9.

The top wall 68 of the digester is provided with an opening I39 (Fig. 2) through which periodically to introduce the source-material through a hopper F32 into the topmost deck 12' substantially at the rate at which the material travels through the successive decks $2 of the digester from the top deck to the bottom deck thereof. The opening #3 3 in the top cover Ell of the digester may. if desired, be provided with a gate not shown) which may be kept closed, except hen charging the topmost deck [2' of the digesterwith source-material. For the discharge of the converted material from the digester, the

bottom wall I4 of the lowermost deck I2 is provided with an opening (not shown) and a hopper I36 (Fig; 1). If desired, the discharge opening in the lowermost deck I2 may be provided with a gate (not shown) which may be kept closed, except during the discharge of theconverted material from the digester. For inspection, test and other purposes, each deck I2 may in its side wall I6 be provided with a hatch I40 (Figs. 1 and 4) which may normally be closed by a hinged cover I42.

For thoroughly mixing the source-material and causing its flow through the digester, as well as for providing for its uniform aeration, there are provided in each deck I2 a plurality of plows I50 (Figs. 3 and 4). The plows I50 are in the present instance, arranged in each deck I2 in four groups 9 of a predetermined number each. The plows I50 of each group g in each deck IZ' are carried by a bracket I52, mounted at I54 on the bottom wall I4 of the next higher deck I2 (Fig. 3). The plough-carrying brackets I52 in the topmost deck I2 are mounted on the top cover 60 of the digester as shown in Fig. 3. The

.plows I50 in each and all groups g may be of identical construction, each comprising a knife shank I60 which terminates at its lower end in a laterally projecting scoop I62 (Figs. 3 and 6). The upper end I64 of each plow I50 is preferably cylindrical and journalled in its bracket I52 in the manner shown in Fig. 6. Suitably mounted on the cylinder end I64 of each plow I50 is a worm gear I66 which is in permanent mesh with a worm I68 on a shaft I10, journalled with its opposite ends in the correspondingbracket I52 (Fig. 5). The worm. gears I66 on the plows I50, respectively, of each group g may be received in recesses I12, respectively, in the corresponding bracket I52 and bear against thrust washers I'M, respectively. The outer end of the worm shaft I10 in each plow-carrying bracket I 52 is provided with a hand wheel I10 for turning the worm shaft I70 and thereby causing angular adjustment of the associated plows I50, as will be readily understood. For ready adjustability of the plows I50 in each deck I2, the worm shafts I'I0 therein preferably extend to the outside thereof and there carry their respective hand wheels I'IB. To this end, the worm shafts. I10 in each deck I2 extend through the associated top angle 10 thereof in the manner shown in Fig. 3. In order that the brackets I52 and associated plows I50 in each stationary deck I2 will, on their rotation with the next higher, rotary deck I2, clear the fixed air-inlet and exhaust conduits and 90, respectively, in the stationary deck, these conduits are located below the adjacent brackets I52 and outside the path of rotation of the adjacent outermost plows I50 (Figs. 3 and Simultaneous angular adjustment of the plows of any group 9 in an deck I2 not only brings the scoop ends I52 thereof into difierent scooping relation with the source-material therein, but brings also the broadside of the knife shank I60 of each ofthese plows more or less into confronting relation with the source-material in the deck. In the example shown in Figs. 3 and 4, the plows I50 in any deck I2 are so adjusted that the relatively sharp edges 6 of the knife shanks I60 thereof slice with minimum resistance into the source-material, while the scoop ends I62 of these plows have a maximum scoop action on the material for the flow of the latter at a maximum rate. More thorough mixing of the sourcematerial anda flow of the same at a slower rate is readily accomplished by difierently adjusting the plows, as will be readily understood. It also appears from Fig. 3 that the scoop ends I62 of the plows in consecutive decks I2 project in opposite directions, the plow being thus adjusted in order to direct the flowing source-material the various decks I2 toward the discharge passages 20 therein, respectively, which are arranged in a staggered fashion as more fully explained hereinafter. Inasmuch as the plows I50 in each deck are, through intermediation of the brackets I52, carried by the bottom walls I4 of the next higher deck and by the top cover I60 of the digester, it will readily be understood that the plows in each stationary deck I2 move with the next higher rotarydeck I2", while the plows in'each rotary deck I2" are stationary. Thus, while mere rotation of the rotary decks I2" of the digester brings about agitation of the sourcematerial throughout the digester, such agitation of the source-material in each rotating deck I2" is caused by the impingement of the material therein against the adjacent stationary plows, while agitation of the source-material in each stationary deck I2' is caused by the motion of the plows therein against the material. In order that the source-material in each deck I2 may thoroughly be mixed by the plows therein before it is transferred to the next lowermost deck, the discharge passages 20 in the several decks are preferably staggered in the fashion shown in Fig. 3, i. e., are alternately arranged near the inner and outer peripheries of the bottom walls I4 of consecutive decks I2. In order to afford maximum protection-to the journal bearings 50 of the rotary decks I2" from the corrosive source-material in the digester, there are mounted, at I on the bottom walls I4 of the decks I2 cylindrical baffles I82, respectively, which keep the source-material from these bearings. Each deck may be made of any suitable material, for example, but without limitation, they'may be made of any suitable corrosionresisting alloy steel.

The instant digester secures several important advantages. Thus, the construction ofthe several decks I2 of the dig-ester as individual units permits their easy transportation and ready assembly at the place of the installation of the digester. By rotating the alternate decks I2" of the digester, and mounting the plows in the latter -as described, the plows require no further provisions, but rely for the performance of their function solely on the motive force of the alternate rotating decks I 2". In conclusion, the construction of the several decks I2 of the digester in individual units not only facilitates the transportation and installation of the digester, but also greatly simplifies the overall digester structure. 'Moreover, by solely relying on the motive forceof the rotating decks I2" of the digester for the agitation of the source-material therein, and in view of the drive of these rotating decks I12" at their outer peripheries, the power consumption requisite for the agitation and flow of the source-material in the digester by the plows therein is extremely low. The low power consumption by the instant digester for its performance is quite important, since the source-material requires for its travel through the digester under constant agitation several days during which the rotating decks I2" will ordinarily be driven continuously.

While we have shown and described the preferred embodiment of our invention, it will be understood that various changes may be made in the present invention without departing from the underlying idea or principles of the invention within the scope of the appended claims.

Having thus described our invention what we claim and desire to secure by Letters Patent, is: 1. A material digester for the conversion of organic materials into fertilizer, comprising a plurality of containers disposed in succession about a common axis, said containers having a bottom wall and affixed side walls, said succession of containers being formed as individual units and sealed from the outside of the digester, each container having a passage for the displacement of material therefrom into the next lower, container and alternate ones of said containers being mounted for rotation in their superposed; relation with the other containers, plows dependingly carried by said containers, respectively, and projecting into the next lower containers, respectively, for displacing the material in the respective containers toward the respective passages therein on relative rotation between said rotary and other containers, means for driving said romeans responsive to the temperature in the interior of said containers, respectively, during the digestion process for operating said valve means.

2. A material dig-ester for the conversion of organic materials into fertilizer, comprising a plurality of containers disposed in succession about a common axis, said containers having a bottom wall and aiiixed side walls, said succession of containers being formed as individual units and sealed from the outside of the digester, each container h-aving'a passage for the displacement of material therefrom into the next lower container and alternate ones of said containers being mounted for rotation in their superposed relation with the other containers, plows dependingly carried by said containers, respectively, and projecting into the next lower containers, respectively, for displacing the material in there-v spective containers toward the respective passages therein on relative rotation between said rotary and other containers, means for driving said rotary containers and each of said con tainers having an outlet for gases and vapors, a control valve for each of said outlets, and means responsive to the temperature in the interior of. said containers during the digestion process for operating said outlet control valves.

3. A material digester for the conversion of or anic materials into fertilizer, comprising a series of superposed containers, said containers having a bottom wall and distinct side walls, each container having a passage for the displacement of material therefrom into the next lower container and alternate ones of said containers being mounted for rotation in their superposed relation with the other containers, plows adjustably carried by said containers, respectively, and projecting into the next lower containers, respectively, for displacing the material in the respective containers toward the respective passages therein on relative rotation between said rotary and other containers, means for driving said rotary containers, and separate means for adjusting said plows in said containers, respectively, for varying the rate at which the material in the respective containers is displaced by the respective plows.

4. A material digester for the conversion of organic materials into fertilizer, comprising a series of superposed containers, said containers having a bottom wall and distinct side walls, each container having a passage for the displacement of material therefrom into the next lower container and alternate ones of said containers being mounted for rotation in their superposed relation with the other containers, plows adjustably carried by said containers, respectively, and projecting into the next lower containers, respectively, each of said plows having a scoop-like end and being rota-tably adjustable into angular positions in which the scoop-like end thereof displaces different amounts, respectively, of the material in the respective container on relative rotation between the latter and the next higher container, means for driving said rotary containers, and separate means for adjusting said plows in said containers.

5. A material digester of the character described, comprising superposed containers, said containers having a bottom wall and side walls, each having a passage for the displacement of mate-rial therefrom into the next lower container, and alternate ones of said containers being mounted for rotation in their superposed relation with the other containers, plows \adjustab-ly carried by said containers, respectively, and projecting into'the next lower containers, respectively, for displacing the material in the respec tive containers toward the respective passages therein on relative rotation between said rotary and'other containers, each of said plows being rotatably mounted on its respective container for angular adjustability of the former, means for driving said rotary containers, separate devices for adjusting said plows in said containers, respectively, for varying the rate at which the material in the respective containers is displaced by the respective plows, each of said devices comprising a worm gear on the associated plow, a shaft rotatably mounted in, and projecting with its outer end to the outside of, the container on which said associated plow is mounted, and being provided with a worm in permanent mesh with said worm gear, and means on the outer end of said shaft for turning the latter.

WILLIAM D. TAYLOR. EDMUND W. VOEGTLIN. CARL E. SCI-ILOSSER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

